Former General Is Undead Knight - Volume 3, Chapter 23: Flander of Human Furniture?

Kazuki’s life was painfully average—just another cog in the nine-to-five grind. His only escape? Binge-reading novels and no-lifing video games.Then he woke up inside one of those novels.Armed with unstable morals, unhinged humor, and a penchant for pettiness, Kazuki is determined to survive, thrive, and maybe cause a little chaos along the way.The world has no idea what’s coming.

Back in 1998, an ordinary person who has been through, tired, cried, and fought, hopes to run down-to-earth and keep up with the trend of the times.

- Description from novelbuddy

As Shin Youngwoo has had an unfortunate life and is now stuck carrying bricks on construction sites. He even had to do labor in the VR game, Satisfy!

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.